Rivers flowing into the Caspian Sea. Caspian Sea (largest lake)

The Caspian Sea is simultaneously considered both an endless lake and a full-fledged sea. The confusion stems from brackish waters and a marine-like hydrological regime.

The Caspian Sea is located on the border of Asia and Europe. Its area is about 370 thousand km 2, the maximum depth is just over one kilometer. The Caspian Sea is conditionally divided into three almost equal parts: South (39% of the area), Middle (36%) and North (25%).

The sea washes simultaneously the Russian, Kazakh, Azerbaijani, Turkmen and Iranian shores.

Shore of the Caspian Sea(Caspian Sea region) has a length of about 7 thousand kilometers, if you count together with the islands. In the north, the low seashore is covered with swamps and thickets, and has multiple water channels. The eastern and western coasts of the Caspian have a winding shape, in some places the shores are covered with limestone.

There are many islands in the Caspian: Dash-Zira, Kyur Dashi, Dzhambaysky, Boyuk-Zira, Gum, Chigil, Khere-Zira, Zenbil, Ogurchinsky, Tyuleniy, Ashur-Ada, etc. Peninsulas: Mangyshlak, Tyub-Karagan, Apsheronsky and Miankale. Their total area is approximately 400 km 2.

It flows into the Caspian Sea more than a hundred different rivers, the most significant are the Ural, Terek, Volga, Atrek, Emba, Samur. Almost all of them provide the sea with 85–95% of the annual drainage.

The largest bays of the Caspian: Kaidak, Agrakhan, Kazakh, Dead Kultuk, Turkmenbashi, Mangyshlak, Gyzlar, Girkan, Kaidak.

Caspian climate

The Caspian Sea is located in three climatic zones at once: subtropical climate in the south, continental in the north and temperate in the middle. In winter, the average temperature varies from -10 to +10 degrees, while in summer the air warms up to about +25 degrees. During the year, precipitation falls from 110 mm in the east and up to 1500 mm in the west.

The average wind speed is 3‒7 m / s, but in autumn and winter it often increases to 35 m / s. The most drained areas are the coastal areas of Makhachkala, Derbent and the Absheron Peninsula.

Caspian Sea water temperature ranges from zero to +10 degrees in winter, and from 23 to 28 degrees in the summer months. In some coastal shallow waters, the water can warm up to 35-40 degrees.

Only the northern part of the sea is subject to freezing, but in especially cold winters, the coastal zones of the middle part are added to it. The ice cover appears in November and disappears only in March.

Problems of the Caspian Region

Water pollution is one of the main environmental problems of the Caspian. Oil production, various harmful substances from flowing rivers, waste from nearby cities - all this negatively affects the state of sea water. Additional troubles are created by poachers, whose actions reduce the number of fish of certain species found in the Caspian Sea.

Sea level rise is also causing serious financial damage to all Caspian countries.

According to conservative estimates, the restoration of destroyed buildings and the implementation of comprehensive measures to protect the coast from flooding cost tens of millions of dollars.

Cities and resorts on the Caspian Sea

The largest city and port washed by the waters of the Caspian Sea is Baku. Among the others settlements Azerbaijan, located in close proximity to the sea, are Sumgait and Lankaran. On the eastern shores there is the city of Turkmenbashi, and about ten kilometers away by the sea is the large Turkmen resort of Avaza.

On the Russian side, the following cities are located on the sea coast: Makhachkala, Izberbash, Derbent, Lagan and Kaspiysk. Astrakhan is often called a port city, although it is located about 65 kilometers from the northern shores of the Caspian Sea.

Astrakhan

Beach recreation in this region is not provided: along the sea coast there are only continuous reed thickets. However, tourists go to Astrakhan not for idle lying on the beach, but for fishing and various types active rest: diving, catamarans, jet skis, etc. In July and August, excursion ships run across the Caspian Sea.

Dagestan

For a classic seaside vacation, it is better to go to Makhachkala, Kaspiysk or Izberbash - this is where not only good sandy beaches, but also a worthy recreation center. The range of entertainment on the seashore from the Dagestan side is quite wide: swimming, therapeutic mud springs, windsurfing, kiting, rock climbing and paragliding.

The only drawback of this area is the underdeveloped infrastructure.

In addition, among some Russian tourists there is an opinion that Dagestan is far from the most peaceful territory that is part of the North Caucasian Federal District.

Kazakhstan

A much calmer environment can be found in the Kazakh resorts of Kuryk, Atyrau and Aktau. The latter is the most popular tourist town Kazakhstan: there are many good entertainment facilities and comfortable beaches. In the summer it is very heat, reaching +40 degrees in the daytime, and dropping only to +30 at night.

Disadvantages of Kazakhstan as tourist country- the same bad infrastructure and rudimentary transport links between the regions.

Azerbaijan

The most the best places for recreation on the Caspian coast, Baku, Nabran, Lankaran and other Azerbaijani resorts are considered. Fortunately, everything is fine with the infrastructure in this country: for example, in the area of ​​the Absheron Peninsula, there are several modern comfortable hotels with swimming pools and beaches.

However, in order to enjoy a vacation on the Caspian Sea in Azerbaijan, you need to spend a lot of money. In addition, it is possible to get to Baku quite quickly only by plane - trains rarely run, and the journey from Russia itself takes two or three days.

Tourists should not forget that Dagestan and Azerbaijan are Islamic countries, so all "unbelievers" need to adjust their usual behavior to local customs.

Subject to simple rules stay nothing will overshadow your holiday on the Caspian Sea.

Original taken from sibved to the Ancient Caspian. Climate catastrophe of the recent past

Looking through ancient maps, I constantly paid attention to how the cartographers of that time depicted the Caspian Sea. On early maps, it has an oval shape, slightly elongated in latitude, in contrast to its modern form, where the waters of the Caspian Sea stretch from north to south.

Photos are clickable:

Caspian on the map in its modern form

And the size of the Caspian Sea is completely different. The pool area is larger than the modern one.
Let's take a look at a few ancient maps and see for ourselves.

Here the Caspian Sea already has slightly different outlines, but it is still far from the modern ones.

All these maps show that the Caspian Sea has a system of deep rivers flowing into it along the entire perimeter. Now, the main river flowing into the Caspian is the Volga. With so many rivers in the past, this should be a densely populated, fertile land. Ancient cartographers could not be so wrong in the geometric shapes of the reservoir and in the number of rivers flowing into it.
Note that not a single map contains an image, not even a hint of Lake Baikal (this will be useful to us later).
There is no Aral Sea on the maps - it is swallowed up by the Caspian Sea, this is one basin.
It is known that the Aral Sea is rapidly drying up, just catastrophically quickly. About 25 years ago, the USSR even had projects to save this sea by turning Siberian rivers. The coastline of the Aral Sea literally before our eyes, over the years, went beyond the horizon.

The official reason for such a catastrophic decrease in the water level in the Aral Sea-Lake is the huge water withdrawal from the Amu Darya and Syrdarya rivers for irrigation of cotton fields.
More details

Yes, this process is taking place. But not that much. It seems to me that we have witnessed climate change, which began long before excessive human economic activity in this region. Many deserts in this region, steppes are the bottom of the ancient Caspian Sea. But not all. Below I will try to explain why.

In the meantime, I will add information from official science confirming changes in the shape and area of ​​the Caspian basin:

The Russian scientist - academician PS Pallas, having visited the low-lying flat shores of the Northern Caspian, wrote that the Caspian steppes are still in such a state as if they had recently come out from under the water. This idea comes by itself, if you look at these leveled vast spaces, this sandy-clay soil, mixed with sea shells, and countless salt marshes. What sea could flood these steppes if not the Caspian Sea adjacent to them?

Pallas also found traces of a higher standing of the Sea on small hills scattered across the Caspian lowland, like islands in the sea. He discovered on the slopes of these hills, ledges, or terraces. They could only be worked out sea ​​waves valid for a long time.

Soviet scientists have established that on the shores of the Caspian, especially on the east (Mangyshlak and others), there are three coastal terraces at an altitude of 26, 16 and 11 m above the present level of the Caspian. They belong to the last stage of the Khvalynsk Sea, that is, to the period 10 - 20 thousand years ago. On the other hand, there is reliable information about underwater terraces at depths of 4, 8, 12 and 16 - 20 m below the current level.

At a depth of 16–20 m, there is a sharp bend in the transverse profile of the underwater slope, or, in other words, a flooded terrace. The period of such low level sea ​​dates back to the post-Khvalynian time. Later, in the New Caspian time, which began 3 - 3.5 thousand years ago, the level of the Caspian Sea generally increased, reaching a maximum in 1805.

It turns out that relatively recently geological time the level of the Caspian Sea experienced significant fluctuations with an amplitude of about 40 meters.

A large number of coastal ledges - terraces could form only during transgressions (sea advancing on land) and regressions (sea retreat). During the transgression, the sea level remained at a certain height for a long time, and the sea surf had time to process the shores, creating beaches and coastal embankments.

Those. scientists do not deny that even in a very recent geological era, the Caspian Sea was different.

What some figures of the past wrote about the Caspian, let's read:

The first information about the Caspian Sea and its shores was found in the writings of ancient Greek and Roman scholars. However, these information, obtained by them from merchants, participants in wars, seafarers, were not accurate and often contradicted each other. For example, Strabo believed that the Syr Darya flows simultaneously with two branches into the Caspian and into the Aral Sea. In the general geography of Claudius Ptolemy, which was the handbook of travelers until the 17th century, the Aral Sea is not mentioned at all.

Ancient maps of ancient geographers have come down to us. Distances between geographical points were then determined by the speed and time of movement of caravans and ships, and the direction of the path was determined by the stars.

Herodotus (who lived around 484-425 BC) was the first to define the Caspian as a sea isolated from the ocean with the ratio of its width to length as 1: 6, which is very close to reality. Aristotle (384-322 BC) confirmed the conclusion of Herodotus. However, many of their contemporaries considered the Caspian to be the northern bay of the ocean, which, in their opinion, surrounded all the land known then.

Ptolemy (90-168 AD), like Herodotus, considered the Caspian Sea closed, but depicted it incorrectly, in a shape approaching a circle.

Later, in 900-1200. AD Arab scholars, following Ptolemy, presented the Caspian as closed and round. The Caspian (Khazar) Sea can be circled around, returning to the place from which you went, and not encountering obstacles, except for the rivers flowing into the sea, Istakhari wrote. The same was confirmed in 1280 by Marco Polo, the famous Venetian traveler who visited China. As we will see below, a misconception about the shape of the Caspian persisted in the Western scientific world until the beginning of the 18th century, until it was refuted by Russian hydrographers.
Source: http://stepnoy-sledopyt.narod.ru/geologia/kmore/geol.htm

From all this, we can conclude that climatic conditions in this region were different, this is indirectly proved by this map of Africa:

The climate was different not only in Central Asia, but also in the largest desert on the planet - the Sahara. See the huge river that crosses modern desolate Africa from east to west and flows into the Atlantic. In addition, a huge number of rivers flow into the Mediterranean Sea and the Atlantic - this indicates abundant rainfall in this region, and at least the savannah vegetation. The Arabian Peninsula, too, is full of rivers and vegetation.
And this is the climate of the not so distant past, of the past, when people made maps in full.

What could have happened that changed Central Asia, northern Africa beyond recognition? Where did so much sand come from in the Karakum Desert, Sahara?

I will put forward a version based on these cards, which at first glance may be incomprehensible:

It can be seen that the Black Sea and the Caspian are united into one basin and a huge water area flows into them from the northeast and in the center - a huge river flowing from somewhere in the north. There is a connection with the Persian Gulf.

These data are confirmed by scientists:

It turned out that for a very long time, measured in millions of years, the Mediterranean, Black, Azov and Caspian Sea made up a huge sea ​​pool connected to the World Ocean. This basin has repeatedly changed its shape, area, depth, split into separate parts and rebuilt again.

The stages of development of this basin in the historical sequence received various, purely conditional, names: the Miocene basin, or the sea that existed in the Miocene time, several million years ago, the Sarmatian, Meotic, Pontic, Akchagyl, Apsheron and the Khvalynsk seas closest to our time.
Source: http://stepnoy-sledopyt.narod.ru/geologia/kmore/geol.htm (B.A. Shlyamin. Caspian Sea. 1954. Geografgiz. 128 p.)

Or this is an image of the post-glacial period, when from the melting of glaciers, the water flowed to the south. But who could have drawn such an accurate map at that time?
Or this is an image of a catastrophe in the very recent past, when the Caspian Sea was at first oval in shape, and then acquired a modern look. In any case, there were streams of water, a huge layer of sand, silt was deposited, deserts and steppes were formed in this region.
With Africa, the issue is more complicated and requires a more complex study.

I will give a good analysis by A. Lorets: “Ancient civilizations were covered with sand” http://alexandrafl.livejournal.com/4402.html which just shows that not so long ago there were cataclysms, information about which real history absent. Perhaps St. Petersburg was covered with silt and sand at this time and for this reason, and Peter I and Catherine - dug up and restored this ancient city.

One of possible reasons what happened, there could have been a fall of a large asteroid into the Arctic Ocean. You can hear about this in this lecture of the "Tainam.net" project "Faroese astroblema. Star wound of the Apocalypse ":

http://www.youtube.com/watch?v=w4cnp1voABE

it is also possible that many mountain systems were formed during this cataclysm. Lake Baikal - too, because it is absent on ancient maps. And local rivers are depicted in sufficient detail.

Caspian Sea- the most big lake on Earth, located at the junction of Europe and Asia, called the sea because of its size. Caspian Sea represents closed lake, and the water in it is salty, from 0.05% near the mouth of the Volga to 11-13% in the southeast.
The water level is subject to fluctuations, currently - about 28 m below the level of the World Ocean.
Square Caspian Sea at present, it is about 371,000 sq km, the maximum depth is 1025 m.

Length coastline Caspian Sea estimated at about 6,500 - 6,700 kilometers, with islands up to 7,000 kilometers. The shores Caspian Sea most of its territory is low and smooth. In the northern part, the coastline is cut by water channels and islands of the Volga and Ural deltas, the shores are low and swampy, and the water surface is covered with thickets in many places. On east coast limestone shores prevail, adjacent to semi-deserts and deserts. The most winding shores are on the western coast in the area of ​​the Absheron Peninsula and on the eastern coast in the area of ​​the Kazakh Bay and Kara-Bogaz-Gol.

V Caspian Sea 130 rivers flow into the river, 9 of which have delta-shaped estuaries. Large rivers flowing into the Caspian Sea are Volga, Terek (Russia), Ural, Emba (Kazakhstan), Kura (Azerbaijan), Samur (Russian border with Azerbaijan), Atrek (Turkmenistan) and others.

Caspian Sea Map

The Caspian Sea washes the shores of five coastal states:

Russia (Dagestan, Kalmykia and the Astrakhan region) - in the west and north-west, the length of the coastline is 695 kilometers
Kazakhstan - in the north, north-east and east, the length of the coastline is 2320 kilometers
Turkmenistan - in the southeast, the length of the coastline is 1200 kilometers
Iran - in the south, the length of the coastline is 724 kilometers
Azerbaijan - in the south-west, the length of the coastline is 955 kilometers

Water temperature

It is subject to significant latitudinal changes, most pronounced in winter, when the temperature varies from 0 - 0.5 ° C at the ice edge in the north of the sea to 10 - 11 ° C in the south, that is, the difference in water temperature is about 10 ° C. For shallow areas with depths less than 25 m, the annual amplitude can reach 25 - 26 ° C. On average, the water temperature is west coast 1 - 2 ° C higher than in the east, and in the open sea the water temperature is 2 - 4 ° C higher than near the coasts.

Climate of the Caspian Sea- continental in the northern part, temperate in the middle and subtropical in the southern part. In winter, the average monthly temperature of the Caspian Sea varies from −8-10 in the northern part to +8 - +10 in the southern part, in summer - from +24 - +25 in the northern part to +26 - +27 in the southern part. The maximum temperature recorded on the east coast is 44 degrees.

Animal world

The fauna of the Caspian Sea is represented by 1809 species, of which 415 are vertebrates. V Caspian Sea 101 species of fish have been registered, and most of the world's stocks of sturgeon, as well as freshwater fish such as roach, carp, and pike perch, are concentrated there. Caspian Sea- habitat of such fish as carp, mullet, sprat, kutum, bream, salmon, perch, pike. V Caspian Sea there is also a marine mammal - the Caspian seal.

Vegetable world

Vegetable world Caspian Sea and its coastline is represented by 728 species. From plants to Caspian Sea predominantly algae - blue-green, diatoms, red, brown, charovy and others, from flowering - zostera and ruppia. By origin, the flora belongs mainly to the Neogene age, however, some plants were introduced into Caspian Sea a person knowingly or on the bottoms of ships.

Mining of oil and gas

V Caspian Sea many oil and gas fields are being developed. Proven oil resources in Caspian Sea are about 10 billion tons, the total resources of oil and gas condensate are estimated at 18 - 20 billion tons.

Oil production in Caspian Sea began in 1820, when the first oil well was drilled on the Absheron shelf. In the second half of the 19th century, oil production began in industrial volumes on the Apsheron Peninsula, then in other territories.

In addition to oil and gas production, on the coast Caspian Sea and the Caspian shelf is also mining salt, limestone, stone, sand, clay.

Ecological problems

Ecological problems Caspian Sea associated with water pollution as a result of oil production and transportation on the continental shelf, the influx of pollutants from the Volga and other rivers flowing into Caspian Sea, the vital activity of coastal cities, as well as the flooding of certain objects due to an increase in the level Caspian Sea... Predatory hunting of sturgeon and their caviar, rampant poaching lead to a decrease in the number of sturgeon and to forced restrictions on their production and export.

CASPIAN SEA (Caspian Sea), the largest on the globe closed reservoir, closed-drain brackish lake. Located on the southern border of Asia and Europe, it washes the shores of Russia, Kazakhstan, Turkmenistan, Iran and Azerbaijan. Due to the size, originality natural conditions and the complexity of the hydrological processes of the Caspian Sea is usually attributed to the class of closed inland seas.

The Caspian Sea is located in a vast area of ​​internal flow and occupies a deep tectonic depression. The water level in the sea is about 27 m below the level of the World Ocean, the area is about 390 thousand km 2, the volume is about 78 thousand km 3. The maximum depth is 1025 m. With a width of 200 to 400 km, the sea is elongated along the meridian by 1030 km.

The largest bays: in the east - Mangyshlak, Kara-Bogaz-Gol, Turkmenbashi (Krasnovodsky), Turkmen; in the west - Kizlyarsky, Agrakhansky, Kyzylagaj, Baku Bay; in the south there are shallow lagoons. There are many islands in the Caspian Sea, but almost all of them are small, with total area less than 2 thousand km 2. In the northern part there are numerous small islands adjacent to the Volga delta; the larger ones are Kulaly, Morskoy, Tyuleniy, Chechen. On the western shores - the Apsheron archipelago, to the south lie the islands of the Baku archipelago, on the eastern coast - the narrow Ogurchinsky island stretching from north to south.

The northern shores of the Caspian Sea are low-lying and very sloping, characterized by a wide development of drylands, which are formed as a result of surge phenomena; here are also developed delta shores (deltas of the Volga, Ural, Terek) with an abundant supply of terrigenous material, the Volga delta with extensive reed thickets stands out. The western shores are abrasive, to the south of the Apsheron Peninsula, for the most part, the accumulative deltaic type with numerous barrows and spits. Southern shores low-lying. The eastern shores are mostly deserted and low-lying, composed of sands.

Relief and geological structure bottom.

The Caspian Sea is located in a zone of increased seismic activity. In the city of Krasnovodsk (now Turkmenbashi) in 1895, there was a strong earthquake with a magnitude of 8.2 on the Richter scale. On the islands and the coast of the southern part of the sea, eruptions of mud volcanoes are often observed, leading to the formation of new shoals, banks and small islands, which are washed away by waves and reappear.

According to the peculiarities of the physical and geographical conditions and the nature of the bottom relief in the Caspian Sea, it is customary to distinguish the North, Middle and South Caspian. The North Caspian is distinguished by exceptional shallowness, it is located completely within the shelf with an average depth of 4-5 m. Even small changes in the level here at low-lying coasts lead to significant fluctuations in the area of ​​the water surface, therefore, the sea boundaries in the northeastern part are shown with a dotted line on small-scale maps. The greatest depths (about 20 m) are observed only near the conditional border with the Middle Caspian, which is drawn along the line connecting the Chechen island (north of the Agrakhan peninsula) with the Tyub-Karagan cape on the Mangyshlak peninsula. In the relief of the bottom of the Middle Caspian, the Derbent depression is distinguished (the maximum depth is 788 m). The border between the Middle and South Caspian Sea runs over the Apsheron rapids with depths of up to 180 m along the line from Chilov Island (east of the Apsheron Peninsula) to Cape Kuuli (Turkmenistan). The basin of the South Caspian is the most extensive area of ​​the sea with the greatest depths, almost 2/3 of the waters of the Caspian Sea are concentrated here, 1/3 falls on the Middle Caspian, in the North Caspian due to shallow depths there is less than 1% of the Caspian waters. In general, shelf areas prevail in the bottom relief of the Caspian Sea (the entire northern part and a wide strip along the eastern coast of the sea). The continental slope is most pronounced on the western slope of the Derbent Basin and almost along the entire perimeter of the South Caspian Basin. Terrigenous shell sands, shells, oolitic sands are widespread on the shelf; deep-water areas of the bottom are covered with silty and silty sediments with a high content of calcium carbonate. In some areas of the bottom, bedrock of the Neogene age is exposed. Mirabilite accumulates in the Ka-ra-Bogaz-Gol Bay.

Tectonically, within the Northern Caspian, the southern part of the Caspian syneclise of the East European platform is distinguished, which is framed in the south by the Astrakhan-Aktobe zone, composed of Devonian-Lower Permian carbonate rocks, lying on a volcanic base and containing large deposits of oil and natural combustible gas. From the southwest, the Paleozoic fold formations of the Donetsk-Caspian zone (or the Karpinsky ridge) are thrust onto the syneclise, which is a protrusion of the basement of the young Scythian (in the west) and Turan (in the east) platforms, which are divided at the bottom of the Caspian Sea by the Agrakhan-Guryev fault (left strike-slip) of northeastern strike. The Middle Caspian mainly belongs to the Turan platform, and its southwestern margin (including the Derbent depression) is a continuation of the Terek-Caspian foredeep of the folded system of the Greater Caucasus. The sedimentary cover of the platform and trough, composed of Jurassic and younger sediments, encloses oil and combustible gas deposits in local uplifts. The Absheron sill, separating the Middle Caspian from the South, is a closing link of the Cenozoic fold systems of the Greater Caucasus and Kopetdag. The South Caspian basin of the Caspian Sea with oceanic or transitional type crust is filled with a thick (over 25 km) complex of Cenozoic sediments. Numerous large hydrocarbon deposits are concentrated in the South Caspian Basin.

Until the end of the Miocene, the Caspian Sea was a marginal sea of ​​the ancient Tethys Ocean (from the Oligocene, the relict oceanic basin of Paratethys). By the beginning of the Pliocene, it had lost its connection with the Black Sea. The North and Middle Caspian were drained, and through them stretched the valley of the paleo-Volga, the delta of which was located in the area of ​​the Apsheron Peninsula. Deltaic sediments have become the main reservoir of oil and natural combustible gas deposits in Azerbaijan and Turkmenistan. In the Late Pliocene, due to the Akchagyl transgression, the area of ​​the Caspian Sea greatly increased and the connection with the World Ocean was temporarily renewed. The waters of the sea covered not only the bottom of the modern basin of the Caspian Sea, but also the adjacent territories. In the Quaternary time, the transgressions (Absheron, Baku, Khazar, Khvalynskaya) alternated with regressions. The southern half of the Caspian Sea is located in a zone of increased seismic activity.

Climate... Strongly stretched from north to south, the Caspian Sea is located within several climatic zones. In the northern part, the climate is temperate continental, on the western coast it is moderately warm, the southwestern and southern coasts lie within the subtropics, on the eastern coast the desert climate prevails. V winter time over the North and Middle Caspian, the weather is formed under the influence of arctic continental and sea air, and the South Caspian is often under the influence of southern cyclones. The weather in the west is unstable rainy, in the east it is dry. In summer, the western and northwestern regions are influenced by the spurs of the Azores atmospheric maximum, and the southeastern regions are under the influence of the Iran-Afghani minimum, which together creates a dry, stable warm weather... Winds of the northern and north-western (up to 40%) and southeastern (about 35%) directions prevail over the sea. The average wind speed is about 6 m / s, in central regions sea ​​up to 7 m / s, in the area of ​​the Apsheron Peninsula - 8-9 m / s. Northern stormy "Baku Nords" reach a speed of 20-25 m / s. The lowest average monthly air temperatures of -10 ° C are observed in January-February in the northeastern regions (in the most severe winters they reach -30 ° C), in the southern regions, 8-12 ° C. In July - August, the average monthly temperatures over the entire sea area are 25-26 ° С, with a maximum up to 44 ° С on the eastern coast. The distribution of atmospheric precipitation is very uneven - from 100 mm per year on the eastern banks to 1700 mm in Lankaran. On the open sea, on average, about 200 mm of precipitation falls per year.

Hydrological regime. Changes in the water balance of an enclosed sea strongly affect the change in the volume of water and the corresponding fluctuations in the level. Average long-term components of the water balance of the Caspian Sea for the 1900-90s (km 3 / cm layer): river runoff 300/77, atmospheric precipitation 77/20, groundwater runoff 4/1, evaporation 377/97, ​​runoff in Kara-Bogaz- Goal 13/3, which forms a negative water balance of 9 km 3, or 3 cm of the layer, per year. According to paleogeographic data, over the past 2000 years, the range of fluctuations in the level of the Caspian Sea reached at least 7 m. -29 m (lowest position in the last 500 years). The sea surface area has decreased by more than 40 thousand km 2, which exceeds the area Sea of ​​Azov... Since 1978, a rapid rise in level began, and by 1996, a mark of about -27 m relative to the level of the World Ocean was reached. In the modern era, fluctuations in the level of the Caspian Sea are mainly determined by fluctuations in climatic characteristics. Seasonal fluctuations in the level of the Caspian Sea are associated with the unevenness of the flow of river runoff (primarily the Volga runoff), therefore, the lowest level is observed in winter, the highest in summer. Short-term abrupt changes in the level are associated with surges, they are most pronounced in shallow northern regions and during storm surges can reach 3-4 m. Such surges cause flooding of significant coastal land areas. In the Middle and South Caspian Sea, surging level fluctuations are on average 10-30 cm, under storm conditions - up to 1.5 m. The frequency of surges, depending on the region, is from one to 5 times a month, the duration is up to one day. In the Caspian, as in any closed water body, seiche level fluctuations are observed in the form of standing waves with periods of 4-9 hours (wind) and 12 hours (tidal). The magnitude of seiche fluctuations usually does not exceed 20-30 cm.

River runoff in the Caspian Sea is extremely unevenly distributed. More than 130 rivers flow into the sea, which on average bring about 290 km 3 of fresh water per year. Up to 85% of the river flow falls on the Volga with the Urals and enters the shallow North Caspian. The rivers of the western coast - Kura, Samur, Sulak, Terek, etc. - give up to 10% of the runoff. Another 5% of fresh water is brought to the South Caspian by the rivers of the Iranian coast. The eastern desert shores are completely devoid of constant fresh flow.

Average speeds of wind currents are 15-20 cm / s, the highest - up to 70 cm / s. In the North Caspian, the prevailing winds create a flow directed along the northwest coast to the southwest. In the Middle Caspian, this current merges with the western branch of the local cyclonic circulation and continues to move along the western coast. At the Absheron Peninsula, the current bifurcates. Its part in the open sea flows into the cyclonic circulation of the Middle Caspian, and the coastal one bends around the shores of the South Caspian and turns to the north, being included in the coastal current that bends around the entire eastern coast. The average state of movement of surface Caspian waters is often disturbed due to variability of wind conditions and other factors. For example, in the northeastern shallow water area, a local anticyclonic circulation may arise. Two anticyclonic eddies are often observed in the South Caspian. In the Middle Caspian in the warm season, stable northwestern winds create a southern transport along the eastern coast. In light winds and during calm weather, currents may have different directions.

Wind waves develop very strongly, since the prevailing winds have a long acceleration length. The excitement develops mainly in the northwest and southeast directions. Strong storms are observed in the open water area of ​​the Middle Caspian, in the areas of Makhachkala, the Absheron Peninsula and the Mangyshlak Peninsula. The average wave height of the highest frequency of occurrence is 1-1.5 m, at wind speeds of more than 15 m / s, it increases to 2-3 m. 10 m.

The water temperature on the sea surface in January - February in the North Caspian is close to the freezing point (about -0.2 - -0.3 ° C) and gradually rises in southbound up to 11 ° С off the coast of Iran. In summer, surface waters warm up to 23-28 ° C everywhere, except for the eastern shelf of the Middle Caspian, where seasonal coastal upwelling develops in July-August and the water temperature on the surface drops to 12-17 ° C. In winter, due to intense convective mixing, the water temperature changes little with depth. In summer, a seasonal thermocline (a layer of abrupt temperature change) forms under the upper heated layer at horizons of 20-30 m, separating deep cold waters from warm surface waters. In the bottom layers of the waters of deep-sea depressions, the temperature is maintained at 4.5-5.5 ° С in the Middle Caspian Sea and 5.8-6.5 ° С in the South all year round. Salinity in the Caspian Sea is almost 3 times lower than in the open regions of the World Ocean, and averages 12.8-12.9 ‰. It should be especially emphasized that the salt composition of the Caspian water is not completely identical to the composition of ocean waters, which is explained by the isolation of the sea from the ocean. The waters of the Caspian Sea are poorer in sodium salts and chlorides, but richer in calcium and magnesium carbonates and sulfates due to the peculiar composition of the salts that enter the sea with river and underground runoff. The highest variability of salinity is observed in the Northern Caspian, where in the estuarine areas of the Volga and the Urals the water is fresh (less than 1 ‰), and as we move to the south, the salt content increases to 10-11 ‰ on the border with the Middle Caspian. The largest horizontal salinity gradients are characteristic of the frontal zone between sea and river waters. Differences in salinity between the Middle and South Caspian are small, salinity slightly increases from northwest to southeast, reaching 13.6 ‰ in the Turkmen Bay (in Kara-Bogaz-Gol up to 300 ‰). Vertical changes in salinity are small and rarely exceed 0.3 ‰, which indicates good vertical mixing of waters. Water transparency varies widely from 0.2 m in estuarine areas large rivers up to 15-17 m in the central regions of the sea.

According to the ice regime, the Caspian Sea belongs to the partially freezing seas. Ice conditions are observed annually only in the northern regions. The Northern Caspian is completely covered with sea ice, the Middle - partially (only in severe winters). Middle border sea ​​ice runs in an arc facing the bulge to the north, from the Agrakhan peninsula in the west to the Tyub-Karagan peninsula in the east. Usually ice formation begins in mid-November in the far northeast and gradually spreads to the southwest. In January, the entire North Caspian is covered with ice, mostly fast ice (motionless). Drifting ice borders fast ice in a strip 20-30 km wide. The average ice thickness is from 30 cm at the southern border to 60 cm in the northeastern regions of the Northern Caspian, in hummock heaps - up to 1.5 m. The destruction of the ice cover begins in the second half of February. In severe winters, drifting ice is carried out to the south, along the western coast, sometimes to the Absheron Peninsula. At the beginning of April, the sea is completely free of ice cover.

Research history... It is believed that the modern name of the Caspian Sea comes from the ancient tribes of the Caspians who inhabited the coastal regions in the 1st millennium BC; other historical names: Hyrkan (Irkan), Persian, Khazar, Khvalynskoe (Khvaliss), Khorezm, Derbent. The first mentions of the existence of the Caspian Sea date back to the 5th century BC. Herodotus was one of the first to assert that this reservoir is isolated, that is, it is a lake. In the works of Arab scientists of the Middle Ages, there is information that in the 13-16 centuries the Amu Darya partially flowed into this sea by one of the branches. Numerous known ancient Greek, Arab, European, including Russian, maps of the Caspian Sea until the beginning of the 18th century did not reflect reality and were actually arbitrary drawings. By order of Tsar Peter I in 1714-15 an expedition was organized under the leadership of A. Bekovich-Cherkassky, who explored the Caspian Sea, in particular its eastern shores. The first map, on which the contours of the coastlines are close to modern ones, was compiled in 1720 using astronomical definitions by the Russian military hydrographers F.I.Soimonov and K. Verdun. In 1731, Soimonov published the first atlas, and soon the first printed guide of the Caspian Sea. A new edition of the maps of the Caspian Sea with corrections and additions was carried out by Admiral A. I. Nagaev in 1760. The first information on the geology and biology of the Caspian Sea was published by S. G. Gmelin and P. S. Pallas. Hydrographic research in the second half of the 18th century was continued by I.V. Tokmachev, M.I. In 1807 published new card Of the Caspian Sea, based on the latest inventories. In 1837, systematic instrumental observations of sea level fluctuations began in Baku. In 1847 the first Full description of the Kara-Bogaz-Gol bay. In 1878, the General Map of the Caspian Sea was published, which reflected the results of the latest astronomical observations, hydrographic surveys and depth measurements. In 1866, 1904, 1912-13, 1914-15, expeditionary research on the hydrology and hydrobiology of the Caspian was carried out under the leadership of N.M. Soviet geologists I.M. Gubkin, D.V. and V.D. Golubyatnikovs, P.A. Kovalevsky; in the study of water balance and sea level fluctuations - B. A. Appolov, V. V. Valedinsky, K. P. Voskresensky, L.S. Berg. After the Great Patriotic War in the Caspian Sea, systematic and versatile research was launched aimed at studying the hydrometeorological regime, biological conditions and the geological structure of the sea.

In the 21st century in Russia, two large scientific centers are engaged in solving the problems of the Caspian Sea. Caspian Marine Research Center (CaspMNITs), established in 1995 by a government decree Russian Federation, conducts research work in hydrometeorology, oceanography and ecology. Caspian Research Institute fisheries(CaspNIRKH) traces its history from the Astrakhan scientific research station [created in 1897, since 1930 the Volga-Caspian scientific fishery station, since 1948 the Caspian branch of the All-Russian Scientific Research Institute of Fisheries and Oceanography, since 1954 the Caspian Scientific Research Institute of Marine Fisheries and Oceanography (CaspNIRO), modern name since 1965]. CaspNIRKh is developing the foundations for the conservation and rational use of the biological resources of the Caspian Sea. It includes 18 laboratories and scientific departments - in Astrakhan, Volgograd and Makhachkala. It has a scientific fleet of more than 20 vessels.

Economic use... The natural resources of the Caspian Sea are rich and varied. Significant hydrocarbon reserves are being actively developed by Russian, Kazakh, Azerbaijani and Turkmen oil and gas companies. There are huge reserves of self-precipitated mineral salts in the Kara-Bogaz-Gol Bay. The Caspian region is also known as a mass habitat for waterfowl and semi-aquatic birds. About 6 million migratory birds migrate through the Caspian Sea every year. In this regard, the Volga delta, the Kyzylagaj, North Cheleken and Turkmenbashi bays are recognized as international land under the Ramsar Convention. The estuaries of many rivers flowing into the sea have unique types of vegetation. The fauna of the Caspian Sea is represented by 1800 species of animals, of which 415 are vertebrate species. More than 100 species of fish live in the sea and estuarine sections of rivers. Marine species are of commercial importance - herring, sprat, gobies, sturgeon; freshwater - carp, perch; Arctic "invaders" - salmon, white fish. Major ports: Astrakhan, Makhachkala in Russia; Aktau, Atyrau in Kazakhstan; Turkmenbashi in Turkmenistan; Bandar Torkemen, Bandar Anzali in Iran; Baku in Azerbaijan.

Ecological state. The Caspian Sea is under a powerful anthropogenic impact due to the intensive development of hydrocarbon deposits and the active development of fishing. In the 1980s, the Caspian Sea provided up to 80% of the world's sturgeon catch. Predatory catches of recent decades, poaching and a sharp deterioration in the ecological situation have put many valuable fish species on the brink of extinction. The living conditions have worsened not only for fish, but also for birds and sea animals (the Caspian seal). The countries washed by the waters of the Caspian Sea are facing the problem of creating a set of international measures to prevent water pollution and developing the most effective environmental strategy for the near future. A stable ecological state is noted only in parts of the sea remote from the coast.

Lit .: Caspian Sea. M., 1969; Comprehensive studies of the Caspian Sea. M., 1970. Issue. 1; Gul K. K., Lappalainen T. N., Polushkin V. A. Caspian Sea. M., 1970; Zalogin B.S., Kosarev A.N. M., 1999; International tectonic map of the Caspian Sea and its framing / Ed. V. E. Khain, N. A. Bogdanov. M., 2003; Zonn I.S.Caspian encyclopedia. M., 2004.

M. G. Deev; V.E. Khain (geological structure of the bottom).

Caspian Sea A short description of the closed salt lake of Eurasia and the largest lake on the planet is presented in this article. A message about the Caspian Sea will help you prepare for your studies.

Caspian Sea: report

This water body is located at the geographic junction of Europe and Asia. The water level is 28 m below sea level. For his long history The Caspian Sea "changed" more than 70 names. And it got its modern name from the ancient tribe of the Caspians, who were engaged in horse breeding and settled along the southwestern shore of the lake.

Salinity of the Caspian Sea not constant: near the mouth of the Volga River, it is 0.05%, and in the southeast, the figure increases to 13%. The area of ​​the water body today is about 371,000 km 2, the maximum depth of the Caspian Sea is 1025 m.

Features of the Caspian Sea

Scientists conditionally divided the lake-sea into 3 natural zones:

• Northern
• Average
• Yuzhny

Each of them has a different depth and composition of water. For example, the smallest part is North. The full-flowing Volga River flows here, therefore the salinity is the lowest here. And the southern part is the deepest, and, accordingly, salty.

The Caspian Sea was formed more than 10 million years ago. It can be called part of the ancient Tethys superocean, which once ran between the African, Indian and Eurasian continental plates. Its long history is also evidenced by the nature of the bottom and geological coastal deposits. The length of the coastline is 6500 - 6700 km, and with the islands up to 7000 km.

The shores of the Caspian Sea are mostly smooth and low-lying. The northern part of the coastline is indented by islands and channels of the Ural and Volga delta. The coast is swampy and low, covered with thickets. The east coast is characterized by limestone shores that adjoin deserts and semi-deserts. The west and east coasts have winding shores.

Where does the Caspian Sea flow?

Since the Caspian is a closed body of water, it is logical that it does not flow anywhere. But 130 rivers flow into it. The largest of them are Terek, Volga, Emba, Ural, Kura, Atrek, Samur.

Caspian climate

The climate is continental in the northern part of the sea, temperate in the middle and subtropical in the southern part. In winter, the average temperature ranges from - 8 ... - 10 (northern part) to +8 ... + 10 (southern part). The average summer temperature ranges from +24 (northern part) to +27 (southern part). On the east coast, the maximum temperature was recorded - 44 degrees.

Fauna and flora

The fauna is diverse and has 1809 species. The sea is inhabited by 415 invertebrates, 101 fish species. It contains most of the world's reserves of pike perch, sturgeon, roach, carp. The Caspian Sea is home to carp, mullet, bream, sprat, perch, kutum, pike, as well as such a large mammal as the Caspian seal.

The flora is represented by 728 species. The sea is dominated by diatoms, brown algae, red algae, blue-green algae, chara algae, ruppia and zostera.

The importance of the Caspian Sea

There are many gas and oil reserves on its territory, the deposits of which are at the development stage. Scientists have calculated that oil resources are 10 billion tons, and gas condensate - 20 billion tons. The first oil well was drilled in 1820 on the Absheron shelf. Limestone, sand, salt, stone and clay are also mined on its shelf.

In addition, the Caspian Sea is popular with tourists. Modern resort zones are being created on its shores, mineral water and mud contribute to the development of health centers and sanatoriums. The most famous resorts are Amburan, Nardaran, Zagulba, Bilgah.

Environmental problems of the Caspian Sea

The waters of the sea are polluted as a result of the production and transportation of gas and oil on the shelf. Also, pollutants come from rivers flowing into it. Poaching of sturgeon caviar led to a decrease in the number of these fish.

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